This invention relates generally to marking a recording surface and more particularly to marking the surface with magnetically attractable particles.
The development of latent magnetic images using magnetically attractable marking particles is known. Typically, a latent magnetic image is formed in a magnetizable layer and is developed by contacting the layer with magnetically attractable marking particles.
The image can be formed by a variety of methods. For example, the layer can be uniformly magnetized and then imagewise heated to a temperature above its Curie point. The heated areas lose their magnetic properties when the Curie point temperature is reached. A latent magnetic image is left behind in the areas not heated.
In another method, magnetic toner particles are xerographically arranged to form an image. The magnetic toner image is brought into contact with a magnetizable layer. The toner magnetizes the layer in an image configuration to form a latent magnetic image.
Magnetic recording heads can also be used to form latent magnetic images. The recording heads can be used as styli.
These and other well known methods of forming and using latent magnetic images are found in U.S. Pat. Nos. 3,749,833 and 3,804,511 to Rait et al.; U.S. Pat. No. 3,472,695 to Kaufer et al.; U.S. Pat. No. 3,611,415 to Nelson; U.S. Pat. No. 3,368,209 to McGlauchlin et al.; U.S. Pat. 3,250,636 to Wilferth; U.S. Pat. No. 3,526,191 to Silverberg et al.; and U.S. Pat. No. 3,185,777 to Rheinfrank.
The development of latent magnetic images with magnetically attractable particles produces images of high quality. However, a marking method and apparatus which avoids the need to create and develop a latent magnetic image is desirable.
It is also known to provide a ribbon coated with heat sensitive material and to impinge the ribbon with laser light on the non-coated side so that the heat of the impinging laser light rapidly vaporizes the heat sensitive material adjacent to the ribbon. The rapid vaporization propels some of the marking material from the ribbon to a marking surface. Images can be produced by this method on the marking surface by using a modulated scanning laser.
This marking method, generally referred to as laser induced flash transfer, is very useful. However, it requires a disposable ribbon and a large energy input. An imaging method and apparatus which avoid the use of a disposable ribbon and which require less writing energy are desirable.